In the past, hair analysis techniques for the detection of trace metals were developed that purported to provide information on an individual's nutritional status. One objection to the use of these techniques is the difficulty of distinguishing between trace metals deposited in hair from the bloodstream and metals which have become embedded in hair through external contact with, for example, water and cosmetic agents. Consequently, these techniques are not considered useful by the medical community for diagnosing nutritional problems, and therefore have not been considered sufficiently accurate to determine the level of a particular trace metal consumed by a subject.
The problems with previous hair analysis techniques have caused reliance on urine and blood analysis techniques for the detection of ingested chemicals, e.g., drugs-of-abuse, medications and toxic chemicals, in a subject. However, these techniques also are known to be disadvantageous in that the duration and intensity of use or exposure cannot be ascertained. Urine and blood analysis, at best, can provide short term information concerning ingested drugs or chemicals such as drugs-of-abuse. In addition, there are also problems with the interpretation of such results. For example, the detection of a low level of ingested chemical in the urine could mean that a subject ingested a small amount of the drug or chemical very recently or a larger amount several days earlier. Thus, chronic drug use cannot be determined with these methods without repeated testing.
In response to the problems of establishing a reliable and accurate method that would measure both the duration and intensity of use of drugs-of-abuse, medications, toxic chemicals, etc., work performed by Dr. Werner A. Baumgartner, as reported in "Radioimmunoassay of Hair for Determining Opiate Abuse Histories", J. Nucl Med 20:749-752 (1979), determined that long-term histories of exposure to drugs-of-abuse can be obtained through the analysis of mammalian body hair, since these substances are "trapped" within individual hair fibers during their synthesis. In this respect, hair was shown to act like a tape recorder, i.e., past exposure histories can be evaluated through sectional analysis of hair samples. It was found that heroin, once in the bloodstream, will find its way into hair as it is synthesized.
Thus, it was discovered in this study and confirmed by subsequent studies that a variety of chemicals, such as drugs-of-abuse, medications, toxic chemicals, etc., hereinafter collectively referred to as "analyte", are trapped by hair during its synthesis and that these substances are "locked up" in hair for essentially the duration of the hair. This was found to be true for head and body hair as well as for other keratinized structures such as fingernails. Suzuki et al., Forensic Sci. International, 24:9-16, 1984. These entrapped substances cannot be washed out of hair, and are completely released only upon the complete, or nearly complete, destruction of the hair fiber.
Prior art methods of extracting an analyte from hair included subjecting the hair to hot methanol solutions (Baumgartner et al., J. Nucl Med 20, 748, 1979) and by overnight incubation of hair in an alkaline or acid medium. D. Valente, et al., Clinical Chemistry, 1952, Vol. 27, No. 11, 1981. Prior methods also include the use of a mortar and pestle to release the entrapped analyte in conjunction with a solvent.
However, solvent extraction procedures suffer from several problems in accurately determining the presence and amount of an ingested analyte. One of these problems is that the solvent extraction methods frequently remove only a small unknown and variable fraction of the total analyte present in the hair sample. Such methods also tend to be time consuming, and generally involve elevated temperatures which may damage the analyte. Another disadvantage is that different analytes require different solvents for extraction. For example, a hair sample containing morphine, phencyclidine ("PCP"), cocaine and marijuana has to be extracted sequentially with several different solvents, which is a very time consuming procedure, particularly since the frequently toxic solvents have to be evaporated in expensive fume hoods before analysis can proceed.
Other methods and studies pertaining to the degradation of hair and hair analysis include:
O. Suzuki, et. al., in a publication by Elsevier Scientific Publishers Ireland Ltd., discloses a method for detecting methamphetamine and amphetamine in nail clippings or hair in which the substance was first washed in a mixture of methanol and water and dissolved in sodium hydroxide, followed by analysis of the extracted drug.
A. W. Holmes, in Textile Research Journal, 706-712, August 1964, discloses the degradation of human hair by papain using sodium sulfite as enzyme activator.
Annette M. Baumgartner. et al., in the Journal of Nuclear Medicine, 20:748-752, 1979, discloses the extraction of morphine and heroin from hair by pulverizing hair with a mortar and pestle followed by treatment with methanol.
D. Valente, et al., in Clinical Chemistry, Vol. 27, No. 11, 1981, discloses Dr. Baumgartner's technique of subjecting hair to a treatment of hot methanol to effectuate extraction of drugs of abuse as well as the author's technique of extracting morphine in an acid or alkaline medium.
A. M. Baumgartner, et al., in Journal of Forensic Sciences, p. 576-81, July 1981, discloses the extraction of PCP with mortar and pestle followed by treatment with methanol. The extracted PCP was then analyzed with RIA.
Smith et al., in Journal of Forensic Sciences, Vol. 26, No. 3, July 1981, pp. 582-586, disclose the testing of hair for the presence of phenobarbital, in which a single head hair was washed, dried, cut in 2 mm lengths and added to 0.2 ml 0.1% SDS/saline solution, and a sample assayed by radioimmunoassay.
W. A. Baumgartner, Black, et al., in J. Nucl Med 23: 790-892, 1982, discloses the extraction of cocaine from hair samples by refluxing the hair samples in ethanol followed by RIA analysis.
Ishiyama, et al., in Journal of Forensic Sciences, Vol. 28, No. 2, April 1983, pp. 380-385, disclose a method whereby hair from methamphetamine addicts was dissolved using 1.5 N hydrochloric acid at a pH between 1 and 2, followed by analysis using a gas chromatograph and mass spectrometry.
K. Puschel, et al., in Forensic Science International, 21 (1983) 181-186, discloses the dissolving of hair samples by exposure to sodium hydroxide and heat followed by analysis for the presence of morphine by RIA.
O. Suzuki. et al., in Journal of Forensic Sciences, Vol. 29, No. 2, April 1984, pp. 611-617, discloses the detection of methamphetamine and amphetamine in a single human hair by gas chromatography and chemical ionization mass spectrometry. The hair sample was first dissolved in a sodium hydroxide solution to which was added N-methylbenzylamine.
N. J. Haley et al., in Clin. Chem. 31/10, 1598-1600 (1985), discloses the analysis of hair for nicotine and cotinine, in which washed hair samples were dissolved in a buffer solution containing gelatin, sodium chloride, Tris and EDTA, and adjusted to pH 7.4. Samples were then analyzed by radioimmunoassay.
Sramek, Baumgartner, et al., in A.M.J. Psychiatry 142:8, August 1985, discloses the analysis of hair samples of psychiatric patients with methanol extraction and radioimmunoassay.
Baumgartner, et al., in Clinical Nuclear Medicine, Vol. 10, Sep. 4, 1985, discloses the benefits of extracting entrapped drugs of abuse from hair followed by RIA analysis.
Gill, et al., in Nature, Vol. 318, p. 577 (1985) discloses the use of an SDS/proteinase k/dithiothreital mixture to extract DNA from whole blood, whole semen, vaginal fluid, hair roots, bloodstains and semen stains. The article states that "no DNA could be isolated from hair shafts".
Smith et al., in J. Forensic Sci. 1986, 31(4), 1269-73, discloses the detection of cocaine in perspiration, menstrual blood stains and hair using RIA.
M. Margio, et al., in "Determination of Morphine and Other Opioids in the Hair of Heroin Addicts by HPLC and MS/MS" at the International Conference, University of Verona, Jun. 25-26, 1986, discloses various methods to assay morphine from hair samples.
M. Marigo, et al., in the Journal of Analytical Toxicology, Vol. 10, July/August 1986, discloses a method for the quantitative determination of morphine contained in the hair of heroin addicts, by means of heat-acid hydrolysis, pre-column dansyl derivatization, straight phase liquid chromatography and fluorescence detection.
Smith, et al., in Journal of Forensic Sciences, Vol. 31, No. 4, October 1986, pp. 1269-1273, disclose a method for the analysis of hair for the presence of drugs whereby hair samples were first washed, cut into small segments, mechanically pulverized for six minutes, refluxed in ethanol and the samples analyzed using radioimmunoassay.
M. Michalodinitrakis, Med.Sci.Law (1987), Vol. 27, No. 1, discloses the detection of cocaine in rats from the analysis of hair samples, which were dissolved upon exposure to 1.5 N HCL, which brought the pH value to 1-2, following incubation with 0.01 N Hcl at 37.degree. C. for one hour.
Pelli, et al., in Biomedical and Environmental Mass Spectrometry, Vol. 14, 63-68 (1987) discloses a procedure for the identification of morphine in the hair of heroin addicts in which hair is treated with diethylether and hydrochloric acid followed by dissolution of the dried extract in methanol.
Higuchi et al., in Nature, Vol. 332, p. 543 (1988) disclose a method for dissolving hair at pH 8 by the action of dithiothreitol, proteinase K, and 2% sodium dodecylsulfate in order to extract DNA from the digest by a complex chemical extraction method.
Also noted are certain patents, e.g., U.S. Pat. Nos. 3,986,926, 3,966,551, 3,939,040 and 3,623,950, which pertain to depilatory agents for the tanning of hides, and disclose the use of certain enzymes, including papain, in the dehairing process.
However, these and other prior art methods have proven disadvantageous for the reasons noted above and/or because they degrade the analyte probes (e.g., antibodies) of biological analytical methods, thereby preventing the use of such highly sensitive analytical techniques.
Thus, there exists a need for an analyte detection method that can rapidly and completely solubilize a certain analyte from keratinized structures of the body such as hair, fingernails and toenails of a subject and which permits direct analysis of the identity of the analyte and the duration of use of the analyte in, or exposure to, a subject, without destroying the analyte of interest and/or an analyte probe of biological analytical methods.